This invention relates generally to radar systems and, more specifically, to radar targeting systems.
Modern-day strike fighters use Synthetic Aperture Radar (SAR)/Ground Moving Target Indication (GMTI) radar imaging systems to target and support engagement of moving ground targets.
Traditional SAR/GMTI radar imaging systems use separate radar GMTI mode data overlaid on SAR map mode image data. The resulting overlay may result in reduced moving target overlay accuracy. For example, moving targets may be portrayed offset from roads upon which the moving targets travel.
Typically, only one of many ground moving target indications can be tracked using known fighter aircraft Ground Moving Target Track (GMTT) modes. Known GMTT mode accuracies are sensitive to sensor bore-sight errors, radome induced errors, and inertial navigation data errors that corrupt line-of-sight targeting. The impact of these errors on the radar""s ability to accurately track a ground moving target have historically degraded targeting accuracy beyond what is practical for the employment of low cost GPS aided weapons. As a result, modern-day strike fighters may experience reduced accuracy in targeting and supporting engagement of multiple ground moving targets through the weather in order to kill a majority of the moving targets.
Recently, a simultaneous SAR/GMTI mode active electronically scanned array (AESA) radar system has been introduced by The Raytheon Company. Raytheon""s radar system provides a better overlay of moving target image data onto SAR map image. However, this system has difficulty generating moving target location information that would allow a self-guided weapon the greatest chance of success.
As a result, there is an unmet need in the art for an accurate moving target targeting system.
The present invention provides a highly accurate moving target locator system.
The present invention includes a system and method for accurately locating moving targets. The system includes a targeting aircraft that has a radar system with a simultaneous SAR radar/moving target mode that simultaneously collects data for generating a SAR map image and precisely locates detected moving targets within the SAR map image. The velocity and direction of detected moving targets are updated repeatedly during the SAR map data collection period needed to generate an image. The targeting aircraft also includes a mapping component that matches the generated image to a stored digital map image which has been preprocessed using an image mensuration process, and generates moving target location information based on the transfer of measured coordinates from the matched reference image and map to the detected moving targets.
In accordance with further aspects of the invention, the system also includes a strike aircraft with self-guided weapons that each have a unique identifier code. Each of the self-guided weapons includes a navigation system and an antenna for receiving moving targets information and weapon/target pairing codes from the targeting aircraft. Each weapon determines a course to an assigned target based on the sent moving targets information and the weapon/target pairing codes. Each of the self-guided weapons navigates according to the associated determined course.
In accordance with other aspects of the invention, each of the detected moving targets information includes moving target velocity and direction. The targeting aircraft sends the moving target velocity and direction updates to the weapons periodically during the map data collection period for each new map, and each weapon""s navigation system determines the course to the assigned target further based on the sent periodic updates of moving target velocity and direction. Each set of moving targets updates includes weapon/target pairing codes that enable individual weapons to select the appropriate update information from the set of updates for their navigation system. The process of map data collection and target/weapon updating repeats continuously while weapons are in flight.
In accordance with still further aspects of the invention, the radar system is a four-channel active electronically scanned array radar system.